Summary The objective of this project is to validate the i-RxTherm?, VisionQuest?s patented functional thermal imaging system that produces biomarkers for early detection of diabetic peripheral neuropathy (DPN). This device is based on the principle that changes in microvascular function are correlated to quantifiable changes in nerve function as expressed in measureable microvascular changes. Diabetes affects an estimated 415 million people worldwide, including more than 29 million Americans. Diabetic patients are at risk for a wide array of complications, including heart disease, kidney disease (nephropathy), ocular diseases (diabetic retinopathy), and diabetic foot (peripheral neuropathy). Fifteen percent of diabetics will develop a foot ulcer as a result of peripheral neuropathy during their lifetime. Foot ulcers are the main cause (85%) of lower extremity amputation in patients with diabetes. In Phase I of this project VisionQuest developed and tested the i-RxTherm?. Phase I results demonstrated that the i-RxTherm? produced biomarkers to detects early signs of DPN. Our results showed that the i-RxTherm? can differentiate between normal controls and patients with DPN with high sensitivity and specificity. Furthermore, we demonstrated that the i-RxTherm? identified diabetics who were undiagnosed with DPN but who were later confirmed to show early to moderate signs of DPN. In Phase II of this project, our objective is to validate these results in a larger cohort of subjects, and to develop a low-cost clinical prototype that can be used in the primary care setting. There are three specific aims to be accomplished in this grant application. The first aim is to identify and quantify specific biomarkers of levels of severity or stages of DPN. To achieve this aim we will collect data from 136 subjects that will include normal controls and patients diagnosed with DPN. The second aim is to collect data from 240 diabetics with previously undiagnosed DPN and to demonstrate that our classification methodologies identify patients with diabetes who present with early to moderate signs of DPN and who have not been previously diagnosed for the disease. In the final aim, we will develop and test a low-cost version of the i-RxTherm? that can be used in the primary care setting. At the end of this project we will have a fully validated device that will provide a more effective means of screening and early detection of DPN.